Endodontic treatment is largely performed on teeth significantly affected by caries, multiple repeat restorations and/or fracture. Already structurally weakened, such teeth are often further weakened by the endodontic procedures designed to provide optimal access and by the restorative procedures necessary to rebuild the tooth. It is therefore accepted that endodontically treated teeth are weaker and tend to have a lower lifetime prognosis. They require special considerations for the final restoration which involve ensuring both adequate retention for the final restoration and maximum resistance to tooth fracture.

1. RECONSTRUCTIONOF ENDODONTICALLY TREATED
TEETH
DR. KUMARI KALPANA
PG-II
1

2. CONTENTS
 Introduction
 Definition
 Vital Vs. Endodontically Treated Teeth
 Aims And Objectives of Reconstruction
of Endodontically Treated Teeth
 Evaluation Of Endodontically Treated
Teeth
 Factors Influencing The Selection Of
Restorative Procedures For
Endodontically Treated Teeth
2

3.  Classification Of Post Systems
 Principles Of Post Space Preparation
 Keys To Post & Core Success
 Post And Core Fabrication
 Treatment Options For Reconstruction
Of Endodontically Treated Teeth
 Failure Of Posts
 Advancements In Post Systems
 Conclusion
 References
3

4. INTRODUCTION
4

5. 5
 Endodontic treatment is largely performed on teeth significantly
affected by caries, multiple repeat restorations and/or fracture.
Already structurally weakened, such teeth are often further
weakened by the endodontic procedures designed to provide optimal
access and by the restorative procedures necessary to rebuild the
tooth.
 It is therefore accepted that endodontically treated teeth are weaker
and tend to have a lower lifetime prognosis. They require special
considerations for the final restoration which involve ensuring both
adequate retention for the final restoration and maximum resistance
to tooth fracture.

6. DEFINITION1
6
1. The glossary of prosthodontic terms. J. Prosthet Dent 2005;94(1):1-83.

7. A post usually made of metal or fiber-reinforced composite
resin that is fitted into a prepared root canal of a natural
tooth; when combined with a core, it provides retention and
resistance for an artificial crown, it is also used as a platform
for retentive attachment systems and for a non-retentive
over-denture post-coping. (GPT-9)
7
Post

8. 1. The center or base of a structure
2. The foundation restoration which
restores sufficient coronal anatomy of a
vital or endodontically treated tooth
8
Core

9. A post with incorporated core; it provides retention and resistance for an
artificial crown; it is also used as a platform for retentive attachment
systems and non-retentive over-denture abutments. (GPT-9)
9
Post-and-core

10. Post-core crown:
1. A post-retained crown made for an endodontically treated tooth that uses a
porcelain facing;
2. An artificial crown with an attached metal post that fits the prepared natural
tooth and inserts into the endodontically treated root canal (GPT-9)
Ferrule:
A band or ring used to encompass the root or crown of a tooth (GPT-9)
10

11. HISTORICAL BACKGROUND
 In the 1700s Fauchard inserted wooden dowels in
canals of teeth to aid in crown retention.
 The replacement crowns were made from bone, ivory,
animal teeth, and sound natural tooth crowns.
 ‘‘Pivot crown’’ Porcelain pivot crowns were described
in the early 1800s by a well-known dentist of Paris,
Dubois de Chemant.
 Sir John Tomes in 1849 -Tomes’ post length and
diameter conformed closely to today’s principles in
fabricating posts.
11
Fig. showing replacement crowns
proposed by Fauchard

12.  The Richmond crown was introduced in 1878 and incorporated
a threaded tube in the canal with a screw-retained crown.
 It was later modified to eliminate the threaded tube and was
redesigned as a 1-piece dowel and crown (Hampson EL et al;
1958, and Demas NC et al; 1957), which lost its popularity
quickly because they were not practical. This was obviously
evident when divergent paths of insertion of the post space and
remaining tooth structure existed, especially for abutments of
fixed partial dentures.
12
Fig. showing 1-piece dowel and crown

13.  1930’s, the custom cast post and core was developed to replace
one-piece post crowns. This procedure required casting a post and
core as a separate component from the crown.
 Glass fiber- supported resin post systems were introduced in 1992.
 In 1999, the endocrown was described for the first time by BINDL
and MORMANN as adhesive endodontic crowns and characterized
as total porcelain crowns fixed to endodontically treated posterior
teeth.
13

14. VITAL VERSUS ENDODONTICALLY TREATED TEETH2
14
2. Huang TJ, Schilder H, Nathanson D. Effects of moisture content and endodontic treatment on some mechanical
properties of human dentin. J Endodon 1991;18:209–15.

15.  Loss of tooth structure
 Loss of physical characteristics
 Altered esthetic characteristics
15

16. Classic studies quoted that:
“Dentin in endodontically treated teeth is substantially different
from dentin in teeth with vital pulps”
Schwartz RS. Robbins JW. Post Placement and Restoration of Endodontically Treated Teeth: A Literature Review. JOE; 2004;30:289-301.
16
Loss of physical characteristics

17. (1) Loss of water from the teeth.
(2) Loss of collagen cross linking.
17
• Cuspal deflection that can occur during function
Buccal Lingual

18. Huang TJ, Schilder H, Nathanson D. Effects of moisture content and endodontic treatment on some
mechanical properties of human dentin. J Endodon 1991;18:209–15.
Compared the physical and mechanical properties of dentin specimen from teeth with and
without endodontic treatment at different levels of hydration and concluded:
“neither dehydration nor endodontic treatment caused degradation of the physical
and mechanical properties of dentin.”
18

19. Architectural changes
Loss of structural integrity associated with the access preparation.
Loss of Neuro-sensory feedback
A protective feedback mechanism that is lost when the pulp is removed,
which may contribute to tooth fracture.
Randow K, Glantz P. On cantilever loading of vital and non-vital teeth. Acta Odontol Scand 1986;44:271–7
19

20. Altered esthetic Characteristics
 Darkening of the non vital teeth is a common clinical finding.
 Bio-chemically altered dentin modifies light refraction through the tooth
and correspondingly modifies its appearance.
20

21. Restoration
of tooth
function and
aesthetics.
Resist
functional
load.
Maintenance
of periodontal
health.
AIMS OF RECONSTRUCTION OF ENDODONTICALLY
TREATED TEETH:
21

22. EVALUATION OF ENDODONTICALLY TREATED TEETH
 Good apical seal as revealed by radiographs.
 No sensitivity to pressure.
 No active inflammation
 No fistula
 No exudate
 No periodontal disease
Rosensteil, Land and Fujimoto. Contemporary Fixed Prosthodontics. 2nd Ed.; Mosby, St. Louis, 1995.
22

23. FACTORS INFLUENCING THE SELECTION OF RESTORATIVE
PROCEDURES FOR ENDODONTICALLY TREATED TEETH5,6
 The amount of remaining tooth structure.
 The anatomic position of the tooth.
 The functional load on the tooth.
 The esthetic requirements for the tooth.
23
5. Robbins JW. Restoration of the endodontically treated tooth. Dent Clin N Am 46 (2002) 367–
384.

24. THE AMOUNT OF REMAINING TOOTH STRUCTURE
 Tooth structure loss can range from
Minimal
access
preparation
Extensive
damage
Endangered
longevity
24

25. More than half tooth
structure INTACT
Restored conservatively with
coronal restoration
25

26. More than half tooth
structure LOST
Post and core is indicated
26

27. Two factors influence the choice of technique:
The type of tooth
(whether incisor, canine,
premolar or molar ) The amount of remaining
coronal tooth structure
27

28. THE ANATOMIC POSITION OF THE TOOTH
Anterior teeth :
Anterior teeth with minimal loss of tooth structure may be restored
conservatively.
Endodontically treated anterior teeth is to receive a crown, a post often is
indicated.
Reason: The remaining coronal tooth structure is quite thin after it has received
root-canal treatment and been prepared for crown.
Also anterior teeth must resist lateral and shearing type of forces and pulp
chamber are too small to provide adequate retention and resistance without
the post.
28

29. Posterior teeth :
Molars teeth receive predominantly vertical rather than shear forces.
Unless a large percentage of coronal tooth structure is missing, posts are
rarely required in endodontically treated molars
When post is required due to lack of coronal tooth structure, it should be
placed only in the largest canal i.e palatal canal in maxillary molars and
distal canal in mandibular molar.
Vertical
forces
29

30. FUNCTIONAL LOAD ON THE
TOOTH
The horizontal and Torquing forces endured by abutments for fixed or removable partial
dentures dictate more extensive protective and retentive features in the restoration;
Similarly teeth that exhibit extensive wear from bruxism, heavy occlusion, or heavy
lateral function require full complement of dowel, core and crown.
30

31. ESTHETIC REQUIREMENTS OF THE TOOTH
 Anterior teeth, premolars and often maxillary 1st molar inhabit the
esthetic zone of the mouth.
 Restorative materials for these teeth include tooth colored composite
resin cores, tooth colored cements and various porcelain or ceramic
crown materials.
31

32. INDICATIONS
FOR POST
AND CORE
TREATMENT
Anterior tooth:
 Where the natural crown of root-filled teeth
either has been lost or is extensively
damaged.
 When the root filled tooth is to be used as
bridge abutment.
 Intact natural teeth crown grossly discolored
and destined to receive a crown.
 Loss of two proximal surfaces with a lingual
endodontic access opening which weakens
the tooth.
32

33. Posterior tooth:
 Indicated when remaining coronal portion is sufficient to support
the restoration and sufficient long thick root structure is present.
 When root filled tooth is to be used as an abutment for bridge.
 Indicated in restored bicuspids that endodontically involved.
 A shortened tooth- due to the nature of destruction or removal of
undermined, undesirable tooth structure.
 When there is a vital tooth with insufficient retention for a
conventional crown.
 Indicated in favorable periodontal and periapical conditions with
good oral hygiene.
33

34. CONTRAINDICATIONS:
 Severe curvature of the root e.g., dilacerations of the root.
 Persistent periapical lesion
 Poor periodontal health
 Poor crown to root ratio
 Weak/fragile roots
 Teeth with heavy occlusal contacts
 Patients with unusual and occupational habits
34

35. RATIONALE OF RESTORATION OF
ENDODONTICALLY TREATED TEETH
 It is a common misconception that posts are placed in endodontically
treated teeth in order to strengthen the tooth structure.
 Numerous studies showed that posts do not strengthen the root. The studies
demonstrate that the incorporation of a post within the remaining root
structure will actually weaken the tooth.
35

36.  The primary purpose for a post is to retain a core that can be used
to support the final restoration. Therefore, the rationale for placing
the posts is shifting to their capacity to provide additional retention
and resistance to the displacement of the core material.
 A post is not necessary when substantial tooth structure is present
after a tooth has been prepared.
36

37. DISADVANTAGES OF ROUTINE USE OF
CEMENTED POST
37

38. POST & CORE SYSTEMS
38

39. IDEAL PROPERTIES OF POST:
Wagnild et al (2002) summarized the ideal physical properties of a post that include:
 Maximum protection of the root.
 Adequate retention within the root.
 Biocompatible / noncorrosive
 Maximum retention of the core and crown.
 Maximum protection of the crown margin cement seal.
 Radiopaque
 Not create stresses in the remaining tooth tissue during preparation and
cementation.
 Allow an even distribution of all functional stress.
 Include provision to ensure appropriate support and retention of the core.
39

40. CLASSIFICATION OF POSTS
40

41. Dental post
Type of material
Rigid
Non rigid
Shape
Parallel
Tapered
Combination
Surface characteristics
Threaded
Smooth
Method of fabrication
Prefabricated
Custom post
Amount of
remaining tooth
structure
Class I
Class II
Class III
Class IV
Class V
41

42. 42
Fig. showing forces on rigid and non-rigid posts
•Rigid
•Non-rigid
•RIGID POST SYSTEM:
•Metal
- custom cast
- prefabricated
•Non-metal
- Zirconium
- Ceramic
RIGID NON- RIGID
1)According to material used:

43. 43
• NON-METALLIC POSTS / TOOTH-COLORED POSTS
1. Zirconium-coated CFP,
2. Aesthetic-Post Plus (Bisco);
3. The all-zirconium posts,
4. Cosmopost (Ivoclar) and Cerapost (Brasseler); and
5. Fiber-reinforced posts, Light-post (Bisco), Luscent Anchor (Dentatus) and
Fibrekor Post (Jeneric Pentron).

44. Passive/ Smooth Tapered Posts
 The essential guideline in post placement is to maintain as much
natural peri-canal tooth structure as possible. The post that best
meets this requirement is the passive tapered post, because it
mimics the natural canal shape, because of its shape it provides the
least amount of retention (Johnson JK et al; 1978, and Standlee
JP et al; 1978).
44
Based on shape and surface characteristics

45. 45
The wedging effect of the post is related to the flare of the post channel:
the greater the flare, the higher the wedging effect.

46.  When there is adequate canal length for axial retention (8 to 9 mm)
and the canal is not funnel shaped the tapered post is an ideal choice.
 Also preferred in:
(1) small circular canals,
(2) teeth not subjected to high functional and parafunctional loads, and
(3) in teeth with thin root walls, that are perforated or have perforation
repairs.
 It is especially useful in the restoration of maxillary premolars, due
to their thin, fragile, fluted, and tapered root form (Yaman P et al;
1986, Zillich R et al; 1985, and Raiden G et al; 1999).
46

47. Passive/Smooth Parallel Posts
47
 The parallel post has had a long history of successful use, and it is the post
by which all others are measured (Torbjorner A et al; 1995, Cooney JP et al;
1986, Standlee JP et al; 1978, Raidan G et al; 1999, Sorenson JA et al; 1984, and
Isador F et al; 1999).
 It provides greater retention than the tapered post. The drawbacks of this
type of posts are they lack of venting (except for the Para Post) and less
conservation of tooth structure.
 A parallel post is therefore recommended when there is a need for increased
retention, circular canal, and preparation of the parallel canal space will
not jeopardize the root integrity in the apical one third.

48. Active Posts:
 Active posts derive their primary retention directly from
the root dentine by the use of threads.
These are further available in following two types:
 Threaded tapered
 Threaded parallel
48

49. 49

50. CLASS I
 If all the axial walls of the cavity remains and have a thickness greater than 1mm,
 It is not necessary to insert a post.
Peroz I. Lange KP. Restoring endodontically treated teeth with post and core- a review. Quintessence in. 2005;36:737-746.
50
Depending upon the number of remaining axial cavity walls-

51. CLASS II
Describes loss of one cavity wall.
CLASS III
Represents mod cavity with two remaining cavity walls
POSTS NOT REQUIRED
51

52. CLASS IV
One remaining cavity wall.
Use of posts is indicated.
CLASS V
A decoronated tooth with no cavity wall remaining.
Necessary to insert the post
52

53. BASED ON THE METHOD OF FABRICATION
I. Custom-cast Posts
II. Prefabricated posts
a) Metal
b) Carbon fibre
c) Ceramic
d) Glass fiber
e) zirconia posts
53

54. MATERIAL ADVANTAGE DISADVANTAGE USE PRECAUTIONS
CUSTOM MADE STRENGTH
BETTER FIT
TIME CONSUMING
COMPLEX
ELLIPTICAL
CANALS
DURING CASTING
CARE TAKEN OF FIT,
NODULES
TAPERED
PREFABRICATED
CONSERVATIVE
STRENGTH
LESS RETENTIVE CIRCULAR
CANALS
NOT FOR
EXCESSIVELY FLARED
CANALS
PARALLEL
PREFABRICATED
STRENGTH
RETENTION
LESS CONSERVATIVE CIRCULAR
CANALS
CARE DURING
PREPERATION
THREADED RETENTION LESS CONSERVATIVE
FRACTURE
WHEN REQD
ADDITIONAL.
RETENTION
CARE DURING
SEATING FOR
FRACTURE
CARBON FIBRE DENTIN BOND
EASY REMOVAL
LOW STRENGTH
MICROLEAKAGE
BLACK COLOUR
UNCERTAIN
ENDODONTIC
TREATMENT
NOT FOR TEETH
UNDER LATERAL
LOAD
ZIRCONIA ESTHETICS
STIFFNESS
UNCERTAIN HIGH ESTHETICS
WOVEN FIBER ESTHETICS
DENTIN BOND
STRENGTH
UNCERTAIN
HIGH ESTHETICS NOT FOR TEETH
UNDER LATERAL
LOAD

55. CLASSIFICATION OF CORE MATERIALS
Cast core Plastic Core
materials
• Metal
55
Machined Core
materials
• Zirconia dowels
• Composite
1. Self cure
2. Light cure
3. Dual cure
• Glass ionomer cement
1. Resin –modified
2. Metal modified
(Cermet)
• Amalgam

56. METAL CORE
Advantages
 They can be cast directly on a prefabricated post hence providing a
restoration with good strength characteristics.
 Indirect procedure can be used, making restoration of posterior teeth easier.
 Post and core is the same unit.
Disadvantages:
 More root fracture
56

57. Amalgam core
Advantages:
 Easily manipulated and can set rapidly.
 Good physical properties : High compressive strength, high tensile
strength.
 Very stable to thermal and functional stresses.
 As an intermediary material, this stability transmits minimal stress to the
residual tooth structure and to the luting material of the final coronal
restoration.
57

58. Disadvantages:
Corrosion
Dark colored
“non-adhesive nature”
of the material,
58
Core buildup with amalgam
Retention for an amalgam core can be obtained from the root
canal system, preserving as much tooth structure as possible.

59. Composite resin core
Advantages:
• Adhesive bonding to tooth structure
and many posts
• Ease of manipulation
• Rapid setting,
• Translucent or highly opaque
formulations.
59
various steps showing Core Build Up with Composite
resin and prefabricated post

60. Disadvantages:
 Polymerization shrinkage and contraction away from the tooth structure can result in
core/tooth marginal opening and microcracks.
 Composite resin is dimensionally unstable and expansion in wet conditions can cause
marginal openings or difficulty in seating final restorations.
 A low modulus of elasticity allows deformation of composite resin under function,
which can damage restorative margins, cause degradation of cement seals, or allow
unacceptable load transfers to the dowel material
60

61. Glass ionomer core
 Glass ionomer based materials are markedly weaker than resin composite and
amalgam materials.
61
Advantages:
Fluoride release
Easy to use
Disadvantages:
Technique sensitive
Low fracture toughness
Sensitive to moisture

62. Resin modified GIC
 Has good mechanical properties
 Low elastic modulous
 Dimensional stability is poor
 Better strength than conventional GIC
 Inferior to amalgam and resin composite
62
Metal modified GIC ( Cermet)
Kumar G, Shivrayan A. Comparative study of mechanical properties of direct core build –up materials. Contemp Clin Dent
2015;6(1):16-20.

63. PRINCIPLES OF POST SPACE PREPARATION4
Conservation of
tooth structure
RETENTION
RESISTANCE
63

64. CONSERVATION OF TOOTH STRUCTURE
Preparation of canal
Excessive enlargement can perforate or weaken the root, which then may split during
cementation of the post or subsequent function.
Preparation of coronal tissue
Every effort should be made to save as much of the coronal tooth structure as possible,
because this helps reduce stress concentrations at the gingival margin.
64

65. Six features of a successful design are
1) Adequate apical seal
2) Minimal canal enlargement
3) Adequate post length
4) Positive horizontal stop
5) Vertical wall to prevent rotation
6) Extension of final restoration margin onto the
sound tooth structure.
65

66. Post
length
Diameter
Surface
texture
Luting
agent
Preparation
of canal
space and
tooth
Dowel
design &
composition
Affected by
66

67. POST LENGTH
1. The post length should equal the incisocervical or
occlusocervical dimension of the crown.11,12
2. The post should be longer than the crown.13
3. The post should be one-third to half of the root length. 14
11.Mondelli J. Piccino AC. Berbert A. An acrylic resin pattern for a cast dowel and core. J. Prosthet. Dent.
1971;25:413-417.
12. Sheets CE. Dowel and core foundations. J Prosthet Dent 1970;23:58--65.
67

68. 5. The post should be two-thirds of the root length.15
6. The post should be two-third to three-fourth of the root.
7. The post should be as long as possible without disturbing the apical
seal.4
68

69. Concluding….
I. Keep the length of the post 2/3rd of length of root with 5 mm of apical
gutta percha.
II. Keep the length of the post 2/3rd of length of root with minimum of 3mm
of apical gutta percha.
III. In other cases, the length of the post should at least be equal to the length
of crown or half the length of root.
IV. In periodontally compromised conditions, the length of the post should at
least be apical to the crest of the bone.
69

70. • Increasing the post diameter in an attempt to increase retention is not
recommended.
• The overall prognosis is good when post diameter does not exceed
one third of the cross-sectional diameter of the root.
POST DIAMETER17
70

71. POST DIAMETER17
Conservationist Proportionist Preservationist
Monzavi A. The Effects of Post Diameter on Stress Distribution in Maxillary Central Incisor: A Three Dimensional Finite Element Study. Journal of Dentistry 2004;1:17-23
71

72. THE CONSERVATIONIST
 Minimal instrumentation of canal after removal of gutta percha.
 Instrumentation limited to removal of undercuts in canal.
 Endodontically treated teeth with smaller diameter dowels resist fracture
better.
 Enlarging the canal till clean dentinal shavings extruded from the orifice.
72

73. THE PROPORTIONIST
 The dowel space should not exceed 1/3rd the width of root at its
narrowest dimension.
 They suggested that one third relationship preserved sufficient tooth
structure to resist root fracture.
73

74. THE PRESERVATIONIST
 This philosophy of dowel diameter depends on a minimal thickness of
dentin surrounding the entire dowel to prevent tooth fracture.
 At least 1mm of sound dentin be maintained around the entire
circumference.
74

75. POST SURFACE TEXTURE4:
 The surface characteristic of a post also change its retentive value, the highest
retention is observed with the threaded post , followed by serrated or roughened
post than a smooth one.
 Controlled grooving of the post and root canal considerably increases the retention
of tapered post.
75

76. Retention provided by luting cements:
Zinc phosphate cement < Polycarboxylate cement < G.I.C < Adhesive resin cement
Adhesive resin cements improve the performance of post-and-core restorations.
LUTING AGENTS :
76

77. DOWEL DESIGN & COMPOSITION
Tapered dowel form is generally reserved for the significantly tapered canal system, where
use of a parallel-sided dowel would necessitate rigorous alteration of the radicular dentin
walls.
Parallel-sided dowels also distribute functional loads to the root passively and are therefore
indicated for the majority of cases.
Placement of a parallel-sided dowel within the canal improves both the retention and the
force distribution of the dowel. Parallel-sided dowels are two to four-and-one-half times as
retentive as tapered ones.
77

78. RESISTANCE FORM
• Stress distribution
• Rotational resistance
78

79. STRESS DISTRIBUTION4
 The main function of post and core is to improve resistance to laterally
directed forces by distributing them over as large an area as possible.
 The greatest stress concentrations are found at the shoulder, particularly
interproximally, and at the apex. Dentin should be conserved in these areas if
possible.
 Stresses are reduced as post length increases.
79

80.  Sharp angles should be avoided because they produce high stresses
during loading.
 Threaded posts can produce high stress concentrations during
insertion and loading.
80

81. Stress evaluation of maxillary central incisor restored with
different post materials: A finite element analysis
 Three dimensional finite element models of central incisor, three
posts with crown were constructed on computer with software.
Posts of three different materials (Ni-Cr post, Glass fiber post, and
Zirconia post)with zirconia crown were virtually generated and a
force of 100 N was applied at an angle of 45 degree on the palatal
surface of the crown. Von Mises stresses were evaluated on the
cervical, middle and apical third of the root.
81
Agarwal SK, Mittal R, Singhal R, Hasan S, Chaukiyal K. Stress evaluation of maxillary central incisor restored with diff erent post materials: A fi nite element analysis. J Clin
Adv Dent. 2020; 4: 022-027.

82. 82
Results: The maximum stresses were seen on the cervical one-third
in each post material indicating that this region is more prone to
fracture in tooth restored with posts. Among the three materials
tested, Ni-Cr post showed maximum stress generation followed by
Zirconia post and glass fiber post.
Conclusion: The less rigid post material like glass fiber post can be
used in an endodontically
treated anterior teeth.
Agarwal SK, Mittal R, Singhal R, Hasan S, Chaukiyal K. Stress evaluation of maxillary central incisor restored with different post
materials: A fi nite element analysis. J Clin Adv Dent. 2020; 4: 022-027.

83. ROTATIONAL RESISTANCE
 It is important that a post with a circular cross section
does not rotate during function. In areas where coronal
dentin has been completely lost, a small groove placed in
the canal can serve as an anti-rotational element.
 The groove is normally located where the root is bulkiest,
usually on the lingual aspect.
83

84. KEYS TO LONG TERM SUCCESS WITH
POST & CORE PROCEDURES
• Role of the ferrule
• Biologic width
• Crown – Root ratio
84

85. 1. What is Ferrule?
85

86. ROLE OF THE FERRULE :
•A maximum of 2 mm of dentin axial wall
height.
•Parallel axial walls.
•Metal core must totally encircle the tooth.
•It must be on sound tooth structure.
•It must not invade the attachment apparatus
86

87. The purpose of the ferrule is to improve the structural integrity of
the pulp less tooth by counteracting
Rosen H: Operative procedures on mutilated endodontically treated teeth. J Prosthet Dent 1961;11:973-986.
Sorensen JA, Engelman MJ: Ferrule design and fracture resistance of endodontically treated teeth. J Prosthet Dent 1990;63:529-536
the functional lever forces
the wedging effect of tapered dowels
the lateral forces exerted during insertion of the
dowel
Promoting hugging action,
Preventing the shattering of the root
87

88. CLASSIFICATION OF FERRULE
Jotkowitz A:Rethinking Ferrule:a new approach to an old dillemma.British Dental Journal,2010;209(1):25-33
88

89. Category A: No anticipated risk
Sound dentine walls remaining all around the tooth, with height greater
than 2 mm and with a minimum thickness of 1 mm. Such teeth do not
present an anticipated risk for structural or mechanical failure .
Based on remaining tooth structure
89

90. 90
Category B: Low risk
Compromised or no ferrule present on either proximal surface.
(ie less than 2 mm height and/or 1 mm thickness) OR two
compromised proximal walls on a tooth that undergoes light
lateral loads. Such teeth present low risk for structural or
mechanical failure.

91. 91
Category C: Medium risk
Two compromised proximal walls on a tooth that undergoes heavy
lateral loads OR a compromised buccal or lingual wall on a tooth
that undergoes light lateral loads. Such teeth present medium risk
for structural or mechanical failure

92. Category D: High risk
A compromised buccal or lingual wall on a tooth that undergoes heavy lateral
loads OR a compromised buccal, and lingual wall on any tooth OR a tooth that
has only two adjacent walls or only a single wall remaining. Such teeth present
high risk for structural or mechanical failure and alternate treatment modalities
should be considered and may be more appropriate.
Category X
No ferrule can be established, such that the tooth is non-restorable.
92

93. HOW TO CREATE FERRULE IN A NO FERRULE CASE?
93

94. 1.Crown lengthening
There are two methods:
2.Orthodontic extrusion
94

95.  Gegauff AG(1999) reported although the crown lengthening allows a
ferrule, it also leads to a much less favorable crown to root ratio and
therefore increase leverage forces over the root during function.
 Therefore, creating a ferrule with orthodontic extrusion must be
preferred, although the root is effectively shortened, the crown is not
lengthened.
Gegauff AG.Effect of crown lengthening and ferrule placement on static load failure of cemented cast post-cores and
crowns. J Prosthet Dent 2000;84: 169–179.
95

96. 96

97.  The biologic width is the distance from the
depth of the gingival sulcus to the crest of
the bone (avg- 2.04 mm).
 Maintenance of adequate periodontal
status is necessary for the long term
success.
2. Biologic Width
97

98.  The ratio is defined as the physical
relationship between the portion of the
tooth within the alveolar bone compared
to the portion not within, as determined
radiographically.
 Clinical procedures directly affect the
crown root ratio.
3. Crown-Root ratio: 98

99. METHODS FOR POST AND
CORE FABRICATION
99

100. Preparation of canal space and tooth4
It is a 3 stage operation :
 Removal of endodontic filling material to the appropriate
depth.
 Enlargement of the canal.
 Preparation of the coronal tooth structure.
100

101. Removal of the Endodontic Filling Material
It is recommended that the root canal system should first be completely
obturated and then space made for a post.
Removal of the Endodontic Filling Material
101

102. Instruments for Gutta-percha Removal
1. K-files or H-files
2. Gutta-percha solvent
3. Combination of paper points & gutta-percha
solvent
4. Rotary instruments
a. Gates Glidden drill / Peeso reamer
b. GPX gutta-percha remover
c. NiTi rotary instruments
Khatavkar R. Hedge V. Current concepts in gutta-percha removal for re-treatment. Dental tribune: april-June, 2010:18
102

103. 5. Specialized rotary instruments designed for retreatment
a. ProTaper Universal retreatment instruments
b. Mtwo retreatment files
c. R-Endo retreatment files
6. Heat transfer devices
a. Heat carrier tips
b. Ultrasonic tips
7. Soft tissue laser.
103

104. eucalyptus oil, turpentine, chloroform,
xylol,
methylene
chloride,
orangewood oil,
methyl
chloroform,
endosolv E,
endosolv R, and
tetrahydrofuran
GUTTA-PERCHA
SOLVENTS
104

105. Enlargement of the root canal for a prefabricated post :
 Enlarge the canal one or two sizes with a drill, endodontic file or reamer that
matches the configuration of the post.
 When using rotary instruments, alternate between the peeso-reamer and twist
drills that correspond in size.
 In case of a threaded post, appropriate drill size is followed by a tap that
prethreads the internal wall of the post space.
 Use a prefabricated post that matches the standard endodontic instrument.
105

106. Examples:
 Zirconia posts
 Titanium posts
 Ceramic post
 Cosmopost
 Fiber posts
106

107. Preparation of the coronal tooth structure :
 Remove all the internal and external undercuts that will prevent withdrawal of
the pattern.
 Remove any unsupported tooth structure but preserve as much as crown as
possible.
 Part of the remaining coronal tissue is prepared perpendicular to the post because
it will create a positive stop to prevent over seating or splitting of the tooth.
107

108. FABRICATION OF CUSTOM MADE POST
Direct technique recommended for single canals
Indirect technique more appropriate for multiple
canals
108

109. DIRECT TECHNIQUE
Materials
 Wax with a plastic rod as a carrier (BARKER BC 1963)
 Thermoplastic resin
 Core of acrylic resin with an endodontic file coated with wax that
adapts to the prepared canal (MILLER EZ;1978)
 Light cure composite
 Green stick compound
109

110. DIRECT TECHNIQUE USING AUTO POLYMERISING RESIN
• Plastic dowels are available that are sized to
match the last file used to prepare the canal or
other plastic dowels are also available.
• DURALAY DOWELS are available to carry the
acrylic or wax to form the pattern of the canal .
110

111. 111

112. 112

113. Cast post system with
plastic rod and
thermoplastic resin.
Try-in of plastic rod.
DIRECT TECHNIQUE USING THERMOPLASTIC RESIN4 114

114.  Heat thermoplastic material
 Apply on apical aspect of rod
115

115.  Insert the rod
 Wait for 5-10 seconds reseat
 Inspect for completeness
116

116. Core build up using
auto-polymerising resin
Trimmed to ideal tooth
preparation form
Final preparation.
117

117. DIRECT TECHNIQUE USING GREEN STICK
 Fit the prepared loosely fitting acrylic rod in to the prepared post space.
 Lubricate the canal with petroleum jelly using periodontal probe.
 Soften the green tracing stick over a flame until the material turns clear.
 Apply the small amount of softened green tracing stick to the apical end of
the acrylic rod.
 Fully insert the acrylic rod lined with green tracing stick into the prepared
post space. Lift after 20 seconds and reseat.
 Inspect the post pattern for completeness .
118
GP, Agarwal SK. Custom post and core fabrication: A simplified technique. Uttar Pradesh State Dent J 2009;27(1):5-8.

118. 119

119. DIRECT TECHNIQUE FOR POSTERIORS
All posts should extend beyond eventual preparation.
Roughen one post and lubricate
Fit prefabricated post into prepared canal
A single piece core with auxillary post is cast directly onto the post of one canal. (The
other canals already have prefabricated posts that pass through holes in the core.)
120

120. 121

121. invest
Remove pattern
Grip smooth posts with forceps and remove
Shape it
Build core with auto-polymerising resin
122

122. 123

123. INDIRECT TECHNIQUE
Cut pieces of orthodontic wire to length and
shape them like the letter J
Coat the wire with tray adhesive. Lubricate the canals to
facilitate removal of the impression without distortion
(die lubricant is suitable).
124

124. Using a lentulo-spiral, fill the canals with elastomeric impression
material.
 Seat the wire reinforcement to the full
depth of each post space, syringe in
more impression material around the
prepared teeth, and insert the
impression tray.
125

125. Remove the impression, evaluate it, and pour the working
cast.
126

126. When this post pattern has been fabricated, the wax
core can be added and shaped.
Start from the most apical and make sure that the post
is correctly oriented as it is seated to adapt the wax.
Apply a thin coat of sticky wax to the plastic post and,
after lubricating the stone cast, add soft inlay wax in
increments .
In the laboratory, roughen a loose-fitting plastic post (a
plastic toothpick is suitable) and, using the impression
as a guide, make sure that it extends into the entire
depth of the canal.
127

127. INDIRECT PATTERN FOR MULTIROOTED TEETH
An auto-polymerized resin was applied on the pre-
fabricated acrylic post using brush bead technique
and was repositioned into the palatal canal. The
pattern was slowly withdrawn and then again
seated into place until it snugly fits.
A pre-fabricated acrylic resin post was inserted
into the palatal canal up to the predetermined
length. Root canal surface was coated with a
suitable lubricant.
128

128. The primary pattern was then lubricated with petroleum jelly and placed into
the palatal canal
Auto-polymerized resin was used to build up the remaining core. The
patterns of both the primary post and the core with two auxiliary posts were
invested in a high heat phosphate bonded investment material.
The mesio-buccal and disto-buccal patterns were also placed in their
respective canals.
129

129. 130
Swarnakar A,Agarwal SK et al. Prosthodontic rehabilitation by restoring grossly decayed multirooted tooth
using split cast post and core: A case report. Chronicles Of Dental Research 2015;4(2):36-8.

130. CORE FABRICATION :
The core of a post-and-core restoration replace missing coronal
tooth structure.
 It can be shaped into resin or wax and added to the post pattern
before the assembly is cast in metal.
 Core can be fabricated with the help of :
a) core former
b) plastic filling material.
131

131. CORE FORMER
 For easy and fast preparation of core.
 Permeable to light for complete curing of composites.
 Can be removed easily by using a artery forceps in
twisting movement.
 Can be trimmed easily according to margins
132

132. Core fabrication using core former
133
Fig. shows contouring and
adjustment of occlusion
Fig. showing addition
of composite to the post
Fig. showing fabrication of
core with core former using
composite to the post

133.  To prevent drifting of opposing or adjacent teeth, an endodontically treated tooth
requires a proper provisional restoration immediately following completion of
endodontic treatment.
PROVISIONAL RESTORATIONS
134

134. 135

135. INVESTING AND CASTING4
Casting should be slightly undersized
Cast post-and-core should fit somewhat loosely
in the canal
The post-core pattern is sprued on
the incisal or occlusal end.
136

136. Investing and casting4…
When resin is used, the pattern should remain for 30 minutes longer in the
burnout oven to ensure complete elimination of the resin
Casting defects should not interfere with
seating of the post; otherwise, root
fracture will result.
EVALUATION
137

137. TREATMENT OPTIONS FOR RECONSTRUCTION OF
ENDODONTICALLY TREATED TEETH4,18,23,24,25,26
Post-core
with crown
Onlays
Complete
coverage
crown
All metal crowns
Metal ceramic crowns
All ceramic crowns
Abutment for
RPD
Over
dentures
Endocrown
138

138. ONLAYS 139
ABUTMENT FOR
RPD

139. COMPLETE COVERAGE CROWN
 ALL METAL CROWNS
 METAL CERAMIC CROWNS
 ALL CERAMIC CROWNS
140

140. OVERDENTURES
141

141. 142
ABUTMENT FOR
FPD
ENDOCROWN

142. CEMENTATION OF POSTS
 Zinc phosphate cement
 The most traditional of all cements zinc phosphate has adequate physical
properties, is inexpensive, and easy to use, and remains an excellent choice for
post cementation.
 Compatible with Zinc Oxide Eugenol sealer
 In case of endodontic failure, a metal post that is cemented in the canal space
with Zinc Phosphate is easier to remove and has a lower risk of root fracture
143

143. Zinc Polycarboxylate
1.Provides a weak chemical bond to dentin.
2. Undergoes plastic deformation after cyclic loading.
3. Less retentive in comparison to zinc phosphate; (low compressive strength).
 Polycarboxylate cements have lower compressive (55 to 85 MPa) and
higher tensile (8 to 12 MPa) strengths than zinc phosphate and therefore is
not a first choice (Anusavice KJ et al; 1996).
144

144. 145
 Polycarboxylate cements are hydrophilic and capable of wetting dentinal
surfaces. They exhibit chemical adhesion to tooth structure through the
interaction of free carboxylic acid groups with calcium.
 One could hypothesize that a truly adhesive cement would be less
susceptible to microleakage, but 2 studies have shown a similar degree of
marginal leakage for both polycarboxylate and zinc phosphate cements.

145. Glass ionomer cement
 Provides a weak chemical bond to dentin.
 Fluoride release and anti-cariogenic effect.
 Requires several days or even several weeks to reach it
maximum strength so it’s unsuitable as a luting agent for posts
(Matsuya S et al; 1996).
146

146. Resin-modified glass ionomer cement
 Fluoride release and anti-cariogenic effect.
 Insoluble.
 Provide good retention of prosthesis.
147

147.  Imbibes water and expands with time and there is anecdotal evidence
that volumetric expansion of the cement will fracture all ceramic crowns
and should be avoided for cementation of posts because it will likely
cause vertical root fracture (Miller MB; 1996).
 These cements have compressive and diametral tensile strengths greater
than zinc phosphate, polycarboxylate, and some glass ionomers but less
than resin composite.
148

148. Adhesive resin cement
 There is greater retention for posts cemented with adhesive resins (Duncan JP et
al; 1998).
 Mendota and Eakle (1994) reported that some posts did not seat completely in
post channels because of premature setting of the resin.
 Resin cements have also been suggested as a method to reinforce pulpless teeth.
 Lowest solubility among all cements.
 Highest compressive strength.
 After the development of fiber-reinforced composite posts, adhesive resin cement
systems are a good option for restoring endodontically treated teeth.
149

149. Types of failures
O Loss of retention
O Root fracture
O Post fracture
O Caries
O Periodontal disease
Failure of posts 150

150. Turner4,23 reported 100 failures of post retained crowns and
indicated that post loosening was the most common
 Loosening (59%)
 Apical abcess (42%)
 Dental caries (19%)
 Root fractures (10%)
 Post fractures (6%)
151

151. Parallel v/s Tapered Posts
 Sorenson and Engleman (1990) found that tapered posts caused more
extensive tooth fractures than parallel sided posts.
 Sorenson and Martinoff (1984) determined that the higher success rate was
with parallel-sided, serrated posts and that tapered cast post and cores showed
a higher failure rate which lead to more catastrophic failure.
 Bergman et al(1989) concluded that the design of the cast post and core was
strongly recommended as a cause of failure.
 In a photo-elastic study analysis, Henry (1977) found that parallel sided posts
distribute stress more evenly as compared to tapered posts.
152

152. Removal of existing posts :
Thin-beaked forceps
Ultrasonic removal
Post puller
Masserann kit
If the fractured post is of the threaded type a groove cut in the end of it may enable
it to be unscrewed
153

153. Fractured post
Ultrasonically
powered chisel
Masserann trepan and
ultrasonic chisel.
Masserann trepan
Before After
154

154. RECENT ADVANCES IN POST SYSTEMS27
 A variety of materials have been used for posts ranging from
wooden posts of the 18th-century to metal posts and, more
recently, carbon fiber, glass fiber and ceramic posts.
Jhavar N, Bhondwe S, Mahajan V, Dhoot R. Recent Advances in Post Systems: A Review.JOADMS
2015;1(3):128-36.
155

155. Based on composite materials
• Composite materials are composed of fibers of
-CARBON
- SILICA
• These fibers are surrounded by a matrix of polymer resin, usually
an epoxy resin. They also include light transmitting posts & ribbon
fibre post.
156

156. Silica Fibre Post
- Aestheti Post
- Aestheti Plus
- Para Post
- Snow Post
Light Transmitting Post
- Double Taper Light Post
- Luscent Anchor Post
- Twin Luscent Anchor Post
Ribbon Fibre Post
- Ribbond
The various types of composite materials post can be grouped as:
157

157.  Aestheti Post - It retains a core of
carbon fibre bundle surrounded by
fibres similarly arranged longitudinally.
 Aestheti Plus - It is also composed
entirely of Quartz Fibres. The traditional
posts include white or clear quartz fibers.
 Para Post X Post System - This system
includes prefabricated parallel side
serrated posts. Each of the four posts
incorporates a raised diamond retention
pattern which provides increased
retention and resistance to torque and
oblique forces.
158

158.  Snowpost –
Snowpost is composed of 60%
longitudinally arranged silica zirconium
glass fibres in an epoxy resin matrix. Its
shape is cylindrical and has a 3° tapered
apex. Four diameters of sizes 1 mm, 1.2
mm, 1.4 mm and 1.6mm – are contained
in the complete kit, together with
matching burs. The tapered end is 4 to 6
mm long
159

159. 160
LIGHT TRANSMITTING POST
• Innovative systems have recently been developed for
reconstituting roots with overly flared canals caused by caries
excessive endodontic preparation and to rehabilitate
and structurally weakened teeth.
• These include the light transmitting posts and their main
is to achieve union between the remaining dentine and a light-
cured composite to restore the lost bulk and original strength
the root thereby functioning as a dentin replacement and
structural reinforcement.

160.  Double Taper Light Post
The new DT- Post system (DT for double taper) was designed
with the purpose of providing close canal adaptation with
minimal tooth structure removal by providing a subtle taper. The
DT light post system has fibre optic construction and can be
cemented with light cure or dual cure materials .
161

161.  Luscent Anchor Post System
The Luscent Anchor post (Dentatus) is a fiber-glass, clear resin post that is
designed to refract and transmit natural tooth colors for esthetic post-and-
core foundations. It is formed from glass fibres embedded in resin matrix.
They bond to the composite core crown complex and offer benefits in
transilluminating light, radiolucency, retention and superb aesthetics.
162

162.  BONDABLE REINFORCEMENT FIBER
POST (RIBBON FIBRE POST)
This method uses a bondable
reinforcement fiber, a fourth-generation
bonding agent and a dual-cure hybrid
composite as the core build-up.
Ribbond maintains the natural strength
the tooth and eliminates the possibility of
root perforation. It conforms to the
natural contours and undercuts of the
canal and provides additional
retention.
163

163. • Based on ceramics :
Fibre reinforced resin post systems:
These posts are made of carbon, quartz or glass fibre embedded in a
matrix of epoxy or methacrylate resin.
The main advantage of these posts is that by flexing slightly under
load, they distribute stresses to the root dentine in a more favorable
manner than metal posts.
164

164.  Cosmopost
It is a ceramic post system and is
indicated mostly in aesthetically important
anterior region of maxilla and mandible.
Cylindrically shaped with a conical tip, the
Cosmopost is available in two relatively
wide diameters (1.4 mm and 1.7 mm).
The posts, as manufactured, have a
relatively smooth surface and are
subsequently treated to roughen the
surface, which increases the bond
strength between the post and core,
whether heat pressed or luted .
165

165. CONCLUSION
166

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171. 172